Excavating or digging equipment used in mining, construction and a myriad of other ground engaging operations typically includes a series of spaced apart tooth assemblies which project forward and serve to break up material to be gathered into a bucket of such digging equipment. Such tooth assemblies are typically arranged in side-by-side and horizontally adjacent relation relative to each other.
Such tooth assemblies can take a myriad of shapes and sizes. As used herein, the phrases “tooth” and “wear part” are intended to include lip protectors, lip shrouds, rippers and other ground engaging tools including, but not limited to, ground engaging teeth. For exemplary purposes, this invention disclosure is illustrated and described for use with a two-piece ground engaging tooth assembly. As mentioned, however, the present invention is equally applicable to other ground engaging equipment releasably secured to an edge or lip of a bucket or related digging equipment.
The art recognized long ago the advantages to be gained by constructing each tooth assembly as a two-part system. That is, the art recognized the advantages to be obtained by connecting a tooth or tool to an adapter or support which, in turn, is connected to the bucket of excavating equipment. Typically, the adapter or support is provided with a base portion which is configured for attachment to the forward edge or lip of a bucket and a free ended nose portion. The tooth is typically provided with a blind cavity or socket whereby allowing the tooth to longitudinally fit over and along at least a lengthwise section of the adapter nose portion. The size of the adapter and tooth vary depending upon the particular digging application. Various types of pinning systems have been used to releasably interconnect the tooth and adapter in operable combination relative to each other.
In some operations, such tooth assemblies are subjected to highly abrasive conditions and, thus, experience considerable and rapid wear. Unless the conjuncture between the component parts is properly fitted, wear problems, especially in the socket or cavity of the replacement part and along the nose portion of the adapter, can result. Moreover, the relatively high forces developed during some digging operations furthermore add to the rapid wear of the component parts of the tooth assembly. Additionally, the pinning systems used to interconnect the tooth and adapter can be harmed or even destroyed by excessive loading in field applications which can result in inadvertent separation of the tooth from the adapter nose portion.
Besides wear in the socket or cavity area of the replacement part or tooth, the adapter nose portion can also become worn from use in the field. Accordingly, and when a new replacement part is fitted to a worn nose portion of an adapter, clearances can exist between the adapter nose portion and the digging tooth. As a result, there can be significant movement between the new replacement part and the nose portion of the adapter. This movement furthermore wears on the nose portion of the adapter and increases the loads upon conventional pinning systems due to excessive tooth movements.
In service, and although specific steps can be taken during fabrication of the wear part to prolong their usefulness, a forward cutting edge of the replacement part sometimes quickly wears and becomes dull and, thus, inefficiencies in the digging operation develop thereby requiring replacement of such parts. As mentioned, the two-part construction of such a tooth assembly advantageously allows the tooth to be replaced independent of the adapter. Depending upon conditions, an adapter can be successfully equipped with anywhere from five to thirty replacement teeth to maintain a sharp penetrating edge for the tooth assembly. In the field, replacement of worn teeth is a common and sometimes a daily experience.
Removing or separating a worn or otherwise broken tooth from its support can involve a tedious and often difficult task of pounding or prying an elongated retaining pin from registering apertures in the tooth and adapter. Removal of the retaining pin is typically effected by using a hammer to manually and endwise force the retaining pin from the apertures in the tooth and adapter. Of course, with larger tooth assemblies, the retaining pins are proportionately sized larger thereby adding to the manual effort and, thus, increasing the time and effort involved to effect digging tooth replacement and/or repair. Problems involving the hammer missing the punch or other tool used to removably pound the retaining pin and hitting the hand of the operator are well known. Dangerous splintering of the metal parts used to drive the retaining pin from between the tooth and adapter can also result. Of course, similar problems exist when the retaining pin is again pounded into the apertures to effect reattachment of the replacement part to the adapter. The unavailability of appropriate tools, i.e., hammers and punches, in the field is also a consistent and well known problem.
Many tooth assemblies arrange the retaining pin along a generally horizontal axis. When the tooth assemblies are mounted in side-by-side proximate relation relative to each other across the bucket edge, however, the horizontal disposition of the retainer pin for each tooth assembly only adds to the time and effort required to initially remove the pin, whereby allowing for removal/repair of the worn/broken part of the two-part system and, subsequent reinsertion of the pin into the registered apertures in the replacement part and adapter. Some operators utilize specially designed tools to facilitate removal of the horizontal pins.
It is also known to arrange the retaining pin in a generally vertical orientation. While advantageously enhancing access to the retaining pin, such retaining devices are more susceptible to the forces applied thereto as a result of the generally vertical movements of the bucket during a digging/excavating operation. Moreover, with a vertically oriented pin system, the lower hole or aperture in the replacement part of the two-part digging system is more exposed—as compared to a horizontal pinning system—to the ground surface over which the digging implement or bucket moves during a digging operation.
Typically, changing to a unique tooth design can create considerable hardship on original equipment manufacturers, part distributors, and end users since a new style adapter most likely must also be utilized to accommodate the innovative tooth and attachment device. This can require costly maintenance of multiple part inventories throughout the entire parts distribution system. This can also cause confusion as to which new tooth and pin will fit what adapter, which tool is needed, etc. Those concerns listed above at least partially explains the reluctance of some manufacturers and even end-users to accept and adopt a newer type of tooth assembly, even after considering the advantages such a new tooth assembly design can offer.
Thus, there is a need and continuing desire for a digging tooth assembly wherein the wear part or tooth and adapter are releasably maintained in operable combination relative to each other and for a related method for releasably coupling the tooth to an adapter. Also, there is a need and continuing desire for a tooth assembly wherein the wear part can be removed from and reassembled to the adapter without requiring the use of a hammer. Moreover, there is an even greater need for a new tooth design that can manifest numerous advantages for the manufacturer of the tooth and yet be utilized in combination with either new style adapters or with the existing population of older style adapters in the field.